Mine roof support bar assemblies

ABSTRACT

A mine roof support bar assembly composed of two bars pivotably interconnected at adjacent ends with a hinge pin extending through lugs formed at these ends of the bars. The axis of the pin lies above the longitudinal axes of the bars when the latter are arranged in a co-linear horizontal position. The adjacent ends of the bars have interengageable extensions disposed beneath the lugs with a cavity formed between the extensions and the lugs. The extensions prevent the bars from pivoting downwards away from the horizontal position while the cavity can receive an insert body which is used to secure the bars in an upwardly inclined position.

United States Patent 1 1 Hiilken et al.

[ 1 Oct. 2, 1973 1 MINE ROOF SUPPORT BAR ASSEMBLIES [73] Assignee: Gewerksehaft Eisenhutte Westt'alia,

Westfalia, Germany [22] Filed: Sept. 10, 1971 [21] Appl. No.: 179,373

FOREIGN PATENTS OR APPLICATIONS 660,738 11/1951 Great Britain 248/357 1,033,613 7/1958 Germany 61/45 D 1,086,199 8/1960 Germany 61/45 D 699,297 11/1953 Great Britain 248/357 900,508 7/1962 Great Britain 248/357 Primary Examiner-Dennis L. Taylor AttorneyRichard C. Sughrue et a1.

[57] ABSTRACT A mine roof support bar assembly composed of two bars pivotably interconnected at adjacent ends with a hinge pin extending through lugs formed at these ends of the bars. The axis of the pin lies above the longitudinal axes of the bars when the latter are arranged in a co-linear horizontal position. The adjacent ends of the bars have interengageable extensions disposed beneath the lugs with a cavity formed between the extensions and the lugs. The extensions prevent the bars from pivoting downwards away from the horizontal position while the cavity can receive an insert body which is used to secure the bars in an upwardly inclined position.

2 Claims, 1 Drawing Figure MINE ROOF SUPPORT BAR ASSEMBLIES BACKGROUND TO THE INVENTION The present invention relates to a mine roof support bar assembly.

It is known to use hinged bars in conjunction with support frames in order to support the roof of a mine working. In comparison with a rigid bar hinged bars have the advantage that when a prop or frame is being set in a support position the hinged bars come to rest directly against the roof over a greater length.

Hinged bars are usually utilized at the forward end of support frames nearest the mineral face being worked. The forward bar facing towards the mineral face can be pivoted and clamped by some means in relation the rearmost bar supported by the prop of the frame so as to provide adequate support for the roof.

In a known hinged bar assembly the front bar can be pivoted upwards or downwards as desired, in relation to the rear bar.

In this assembly the bars are locked in position by a pin inserted through aligned bores in lugs formed on the bars. This locking pin is subjected to strain according to the load on the bars and is thus liable to suffer damage. In order to reduce this strain, it has also been suggested that a recess should be provided around the locking pin in the centre of the assembly and a pressure member inserted into the recess. This pressure member is provided with a bore receiving the locking pin and the two bars can thus rest against the pressure member in the vicinity of the locking pin. It is nevertheless frequently difficult to correctly position this pressure member in relation to the bars to enable the aforementioned locking pin to be introduced.

A general object of this invention is to provide an improved mine roof support bar assembly.

SUMMARY OF THE INVENTION According to the invention there is provided a mine roof support bar assembly comprising a first and a second bar, means for pivotably interconnecting the first and second bars, the bars being capable in use, of contacting and supporting a mine roof, and stop means formed on said bars to prevent the bars from becoming inclined from a co-linear relationship in a direction away from the mine roof.

The second bar of the assembly would be carried by a prop of a support frame and lie rearwardly of the first bar facing the mineral face.

The roof of the working does not as a general rule, subside immediately after the removal of the mineral. On the contrary, any noticeable subsidence of the roof is in most cases only observed at a certain distance from the mineral face, and generally afer a relatively long period of time. This is why, with a roof of normal formation downward pivoting of the front or first bar in relation to the rear or second bar should be precluded when the assembly is set. In the majority of cases the front bar already rests against the roof to an adequate extent even when it assumes a horizontal position in relation to the rear bar itself supported by the prop. If the roof subsides shortly after the removal of the mineral, the front bar should be pivoted upwards out of the horizontal position, when the frame is being set, so that the front bar comes to rest against the roof in front of the mineral face.

The assembly of the invention is thus particularly well adapted to these conditions and can follow the course taken by the roof, owing to the fact that the free ends of the bars can only be bent out of the horizontal position towards each other in the direction of the roof but not in the direction of the floor.

The bars preferably have overlapping lugs formed at their adjacent ends and a hinge pin extends through apertures in said lugs.

The stop means is preferably in the form of interengageable extensions provided at the adjacent ends of the bars beneath said lugs. The axis of the hinge pin preferably lies above the common longitudinal axes of the bars in the direction of the mine roof.

According to a further feature of the invention a cavity is provided between the lugs and the extensions, said cavity being adapted to receive an insert body in order to set the bars in an inclined relationship towards the mine roof. Even when the bars are co-linearly aligned the insert body, which is preferably in the form of two wedge members, can absorb the pressures involved.

The invention may be understood more readily and various other features of the invention may become more apparent from consideration of the following description.

BRIEF DESCRIPTION OF DRAWING An embodiment of the invention will now be described, by way of example only, with reference to the accompanying Drawing which is a side elevation of a mine roof support bar assembly made in accordance with the invention.

DESCRIPTION OF PREFERRED EMBODIMENT As shown in the drawing, the assembly consists of a rear bar 10 and a front bar 1 1 pivotably interconnected by a hinge pin 12. The .pin 12 is disposed above the common longitudinal centre of the bars 10, 11 and is received in aligned bores in two overlapping lugs 13, 14 formed at the ends of the two bars 10, 11 respectively.

Underneath the hinge pin 12 the ends of the bars 10, 11 are provided with extensions 15, 16 which engage one another when the two bars 10, 1-1 are in the extended co-linear relationship as depicted in the drawing. A cavity 17 is disposed between the lugs 13, 14 and the extensions 15, 16. The two extensions l5, 16 thus act as stop means to prevent the two bars 10 and 11 from becoming inclined downwards. Nevertheless the bars 10,11 can be pivoted upwards. If, therefore, the roof of a mine working has subsided to a certain extent the lower part of the roof can be contacted by the rear bar 10, which in its turn is carried by a prop of a support frame, not shown in the drawing, while the front bar 11 can be pivoted upwards from the horizontal position until it comes to rest against the higher part of the roof. In order to secure the bar 11 in this higher position an insert body can be placed into the cavity 17. The insert body is preferably in the form of two wedge members driven in from both sides of the assembly.

We claim:

1. In a mine roof support bar assembly of the type comprising a first elongate bar pivotably connected to a second elongate bar with a hinge .pin extending through overlapping apertured lugs at the adjacent ends of the bars; the improvement comprising complementary extension means at the adjacent ends of the bars said extension means disposed beneath and spaced through overlapping apertured lugs at the adjacent ends of the bars; the improvements comprising integral directly interengaging stop means at the adjacent ends of the bars for preventing relative downward pivoting of the bars when the longitudinal axes of the bars are in a substantially colinear relationship and a cavity means formed between said stop means and said lugs for receiving a separate insert to lock the bars in a position where the bars are relatively pivoted in an upward direction. 

1. In a mine roof support bar assembly of the type comprising a first elongate bar pivotably connected to a second elongate bar with a hinge pin extending through overlapping apertured lugs at the adjacent ends of the bars; the improvement comprising complementary extension means at the adjacent ends of the bars said extension means disposed beneath and spaced from the luGs to form a cavity means therebetween, said extension means directly engaging each other when the longitudinal axis of the bars are in a substantially colinear relationship, for preventing relative downward pivoting of the bars, and wherein said cavity means serves to receive a separate insert member to secure the bars in a non-colinear relationship after the bars have been pivoted upward from the colinear relationship.
 2. In a mine roof support bar assembly of the type comprising a first elongate bar pivotably connected to a second elongate bar with a hinge pin extending through overlapping apertured lugs at the adjacent ends of the bars; the improvements comprising integral directly interengaging stop means at the adjacent ends of the bars for preventing relative downward pivoting of the bars when the longitudinal axes of the bars are in a substantially colinear relationship and a cavity means formed between said stop means and said lugs for receiving a separate insert to lock the bars in a position where the bars are relatively pivoted in an upward direction. 